Solarpanels

These days a lot of small solar panels can be easily and cheaply acquired from various sources.

To find out which of these panels I could use for my projects I decided to hook them up to my voltage-datalogger and see how they perform on a sunny day.

Here is an overview of the panels I tested:

On my testing day, around noon I ran my datalogger for about 15 minutes on each panel. The results are shown below:

During testing the clouds were mostly gone, except when I was testing panel B. The outside temperature was around 27 degrees Celsius. I also put a temperature sensor underneath the panels and measured about 55 degrees C in the shade.

Contents

Solar Panel A

Dimensions: 2.5cm x 2.5cm

Open-circuit voltage: 1.6V

Short-circuit current: 18mA

These panels are commonly found in solar powered garden-lights. I was able to get some for AU$2 each and they contained a 100mAh NiMH battery as well as a small charging circuit based on the yX805 chip. The panels are covered with a glass top layer and have no circuit board. The copper terminals are printed on the bottom of the crystalline material so it's very delicate.

Solar Panel B

Dimensions: 6cm x 6cm

Open-circuit voltage: 6V

Short-circuit current: 35mA

These panels are printed on a circuit board and are therefore easy to solder. The top layer is some kind of transparent epoxy. The voltage curve in the graph above shows some fluctuations due to clouds in front of the sun when testing.

Solar Panel C

Dimensions: 12cm x 6cm

Open-circuit voltage: 4V

Short-circuit current: 250mA

These panels are printed on a circuit board and are therefore easy to solder. The top layer is some kind of transparent epoxy.

Solar Panel D

Dimensions: 9.9cm x 6.9cm

Open-circuit voltage: 5.5V

Short-circuit current: 140mA

These panels are printed on a circuit board and are therefore easy to solder. The top layer is some kind of transparent epoxy.